Download Pharmacology MCQs

Pharmacokinetics, Pharmacodynamics, Pharmacology
of Autonomic nervous system drugs, Autocoids
1. The apparent volume of distribution of a drug
a. is usually larger for a basic drug than an acidic drug.
b. is obtained by dividing the dose administered by its free concentration in the
plasma.
c. is inversely related to its elimination half-life
d. may be reduced in cardiac failure.
2. Binding of drugs to plasma proteins show the following characteristics:
a. the bound drug fraction is pharmacologically active.
b. a drug with a larger volume of distribution is more likely to cause overdose
effects than when displaced from plasma protein binding.
c. drug which is bound strongly to plasma protein will also be strongly bound to
tissues.
d. binding capacity can be reduced in advanced liver disease.
3. Drugs administered by the oral route show the following characteristics:
a. for most drugs absorption is by passive diffusion.
b. for most drugs the dissolution rate is the rate limiting step.
c. acidic drugs are mainly absorbed from the stomach.
d. basic drugs dissolve more readily in the intestinal than in stomach fluid
4. The apparent volume of distribution of a drug:
a. is a ratio indicating the relative distribution of the drug between plasma and its
target site.
b. is greater if it is more extensively bound to tissues than to plasma proteins.
c. is directly related to its plasma half-life.
d. is fairly constant over a wide dose range.
5.
a.
b.
c.
d.
Acetylcholine:
has an ester group in its structure.
is inactivated by both acetylcholinesterase and plasma pseudocholinesterase.
is released at the pre-ganglionic nerve endings.
produces a decrease in the force of cardiac contraction.
6. D-tubocurarine:
a. is well absorbed from the GIT.
b. may produce significant ganglion blockade in large doses.
c. actions can be reversed by neostigmine.
d. has been shown to cause histamine release.
7.
a.
b.
c.
d.
Propranolol:
has intrinsic agonist properties.
is a relative specific beta one agonist.
can cause bronchial constriction in asthmatic patients.
is used in essential hypertension.
8. Histamine causes:
a. increased capillary permeability.
b. gastric hyper-activity.
c. bronchoconstriction.
d. hypotension.
9. The following are physiological antagonists of histamine acting on bronchial
smooth muscle:
a. adrenaline.
b. salbutamol.
c. acetylcholine.
d. bradykinin.
10.
a.
b.
c.
d.
Antihistamines antagonize histamine action by:
stimulating the action of histaminase.
competing with histamine for specific receptors.
preventing the release of histamine from the cells.
enhancing the excretion of histamine.
11.
a.
b.
c.
d.
Ephedrine:
can act directly on alpha and beta receptors.
is poorly absorbed orally.
is resistant to the action of penicillamase.
is readily effective against S.aureus.
12.
a.
b.
c.
d.
Propranolol:
is a beta-1 and beta-2 adrenergic receptor blocker.
should be used in care in patients receiving insulin.
is contra-indicated in asthmatic patients.
is extensively metabolized in the liver.
13.
a.
b.
c.
d.
The effects of beta-adrenergic blockade by propranolol include:
decreased release of adrenaline from adrenal medulla.
antagonism of the effects of noradrenaline on the heart.
decrease of symptoms in thyrotoxic patients.
bronchoconstriction in asthmatic patients.
14.
a.
b.
c.
d.
Histamine:
is metabolized by enzyme in the gut.
is chiefly excreted unchanged.
is released in anaphylaxis.
stimulates nerve endings especially those mediating pain and itching.
15. Side effects of chlorpheniramine:
a. drowsiness.
b. sweating.
c. dry mouth.
d. miosis.
16. Atropine and hyoscine:
a. at therapeutic dose may cause dryness of mouth and inhibit sweating.
b. differ in their CNS effects.
c. are contraindicated in glaucoma.
d. are competitive antagonists of acetylcholine at nicotinic sites.
17. Di-isopropyl fluorophosphate:
a. inactivates cholinesterase irreversibly.
b. penetrate the CNS because of its high lipid solubility.
c. causes pupillary constriction.
d. can be absorbed through the skin and mucous membrane.
18. Atropine:
a. acts competitively at muscarinic receptors.
b. dilates the pupil.
c. paralyses accommodation in the eye.
d. causes dryness of the mouth.
19. Hypotension caused by D-tubocurarine is attributed to:
a. its action on the CNS.
b. its blocking action on sympathetic ganglia.
c. the release of histamine.
d. its direct vasodilator action.
20. Noradrenaline:
a. acts on beta-adrenergic receptors on the heart.
b. action is terminated mainly by re-uptake.
c. re-uptake is inhibited by the TCAs.
d. is released from adrenergic nerve endings by tyramine.
21.
a.
b.
c.
d.
If the elimination of a drug follows first order kinetics it indicates:
the drug is eliminated by a single process only.
the drug forms only one metabolite.
the rate of elimination is proportional to drug concentration.
the rate of elimination is constant.
22.
a.
b.
c.
d.
Binding of a drug to plasma proteins:
occurs only with the albumin fraction.
slows down its dissociation from binding sites.
favors elimination of high clearance drugs.
implies a high volume of distribution.
23.
a.
b.
c.
d.
Anaphylactic responses to a drug:
are usually unrelated to the pharmacological effects of the drug.
do not occur if the drug is taken orally.
require prior response to the drug.
are dose dependent.
24.
a.
b.
c.
d.
The following are antihistamines which act on H1 receptors:
cimetidine.
chlorpheniramine.
phenacetin.
mepyramine.
25. Diphenhydramine:
a. may produce sensitization with repeated topical application.
b. produces atropine-like side effects.
c. has anti-motion sickness property.
d.
blocks histamine-induced gastric secretion.
26. Antihistamines should not be used indiscriminately as they are likely to
cause:
a. drowsiness.
b. changes in skin pigmentation.
c. risk of sensitization.
d. malignant skin changes.
27. State true or false:
a. affinity measures the ability of a drug to bind to the receptor.
b. efficiency measures the biological response resulting from the binding of the
drug to the receptor.
c. potency measures the margin of safety of a drug.
d. receptor is the biological component with which a drug interacts.
28. Statement below refers to the distribution of drugs in the body.
a. the greater the degree of ionization of a drug the more extensive will be its
distribution.
b. the placenta acts as an effective barrier to most drugs from the maternal to
the foetal circulation.
c. an acidic drug is more extensively distributed into intracellular fluid than
extracellular fluid.
d. during steady state distribution the free and bound drug fractions are equal in
all body fluids.
29. The following characteristics refer to the renal clearance of drugs:
a. a clearance of basic drugs can be enhanced by alkalinizing the urine.
b. if when urine pH is modified from 5.3 to 7.4, the clearance of a drug
increases from 92 to 183ml/min, this drug is acidic.
c. the greater the lipid solubility of the drug, the greater will be its clearance
value.
d. if active tubular secretion is involved, then plasma protein binding will limit
drug clearance.
30. The time taken to reach steady state concentration when the drug is
administered orally is determined by:
a. the rate of absorption of the drug.
b. the T1/2 of the drug.
c. the dosing frequency.
d. the bioavailability of the drug.
31.
a.
b.
c.
d.
The following drugs undergo significant first-pass effects:
propranolol.
penicillin G.
phenytoin.
tolbutamide.
32. State true of false:
a. noradrenaline is formed from adrenaline by the action of phenylethanolamine
N-methyltransferase.
b. dopamine is formed from L-dopa by the action of tyrosine 3-hydrolase.
c. p-tyrosine is formed from phenylalanine by the action of phenylalanine-4hydroxylase.
d. tyrosine-3-hydroxyalse forms p-tyrosine from phenylalanine.
33. When neostigmine is given to reverse the effects of d-tubocurarine, atropine
is also given to:
a. minimize the fasciculations of skeletal muscles.
b. block muscarinic effects of d-tubocurarine.
c. minimize parasympathetic effects of neostigmine.
d. minimize central effects of d-tubocurarine.
34.
a.
b.
c.
d.
Methacholine differs from acetylcholine:
in its longer duration of action.
is hydrolyzed by AcH esterase at a faster rate.
is resistant to hydrolysis by pseudocholinesterase.
has got predominant muscarinic action.
35.
a.
b.
c.
d.
Catecholamines:
contain O-dihydrobenzene.
produce increase in oxygen consumption.
readily crosses the blood-brain barrier.
are derived from beta-phenylethylalanine.
36. Prazosin:
a. dilates both the arterioles and venules.
b. is a beta-adrenoceptor antagonist.
c. has a t1/2 of 3h.
d. is not extensively metabolized.
37. Prostaglandin E2:
a. causes constipation.
b. causes bronchoconstriction.
c. can protect the gastric mucosal cells against damage from anti-inflammatory
analgesics.
d. desensitizes afferent nerve endings to pain stimulated by bradykinin.
38. Prostacyclin:
a. is converted rapidly to its stable metabolite 6-keto-PGF2
b. found more in the vessel wall than in platelets.
c. causes bronchoconstriction.
d. causes potent vasoconstriction.
39. Propranolol:
a. blocks actions of both endogenous & exogenous sympathomimetic amines.
b. alkylates the receptor by forming a covalent bond.
c. blocks both the alpha and beta receptors.
d. acts only on receptors in the CNS.
40. Non-catecholamine sympathomimetics are:
a. ephedrine.
b. dopamine.
c. phenylephrine.
d.
noradrenaline.
41.
a.
b.
c.
d.
The following drugs combine with the biological components indicated:
physostigmine combines with cholinesterase.
chloramphenicol attaches to the 50S subunit of bacterial ribosomes.
antacids combine with the parietal cells of the stomach.
acetylcholine combines with nicotinic receptors at the neuromuscular junction.
42.
a.
b.
c.
d.
Prostacyclin:
can enhance platelet aggregation.
can inhibit platelet aggregation.
can cause hypotension.
synthesis is inhibited by NSAIDs.
43.
a.
b.
c.
d.
Prostaglandins have a wide range of actions which include:
inhibition of gastric acid secretion.
bronchodilation.
delay onset of labor.
prevent platelet aggregation.
44.
a.
b.
c.
d.
Parasympathetic blockade is enhanced by:
propantheline and cimetidine.
hydralazine and tolbutamide.
D-tubocurarine and succinylcholine.
pilocarpine and bethanechol.
45. If a drug undergoes significant first-pass effect, it means that:
a. the drug is eliminated rapidly by the liver only.
b. the renal clearance of the drug is high.
c. the drug is poorly absorbed when administered.
d. the drug undergoes rapid distribution initially.
46. The following statements refer to the microsomal mixed function oxidase
system:
a. it acts specifically on drugs which belong to the same pharmacological class.
b. the dosage of a drug may have to be decreased if enzyme induction occurs.
c. enzyme inhibition usually occurs more rapidly than enzyme induction.
d. contains multiple isozymes of cytochrome P450.
47. Neostigmine:
a. usually does not cross the blood-brain barrier.
b. inhibits cholinesterase reversibly.
c. is erratically absorbed after oral administration.
d. can be used in the symptomatic treatment of myasthenia gravis.
48. Propranolol is used the treatment of:
a. hypertension.
b. asthma.
c. angina pectoris.
d. allergic skin rashes.
49.
Noradrenaline at adrenergic nerve endings:
a.
b.
c.
d.
is discharged by the process of exocytosis.
is activated by COMT after re-uptake.
is eventually demethylated to adrenaline.
present in the mobile pool is displaced by tyramine.
50. Adrenaline:
a. increases liver glycogenolysis.
b. causes coronary artery spasm.
c. is used for diarrhoea.
d. is the neurotransmitter at adrenergic nerve endings.
51. The general pharmacological properties of non-catechol sympathomimetic
amines include:
a. CNS excitation.
b. anorexia action.
c. vasoconstriction.
d. decrease in heart rate.
52. The following refers to the acetylator status of individuals:
a. variation in the acetylator status follows a normal frequency distribution.
b. inhibition of phenytoin metabolism by isoniazid is greater in fast acetylators.
c. slow acetylators are more likely to experience toxicity induced by acetylated
metabolites.
d. the majority of Chinese in Singapore are fast acetylators.
53.
a.
b.
c.
d.
Malathion:
is metabolized into an inactive derivative in man.
forms a stable complex with nicotinic receptors.
is easily absorbed through the skin.
effects can be antagonized by atropine.
54.
a.
b.
c.
d.
Hyoscine:
is a specific antagonist at nicotinic receptors.
does not produce depression at CNS.
is contraindicated in glaucoma.
causes urinary retention.
55. The bioavailability of a drug:
a. is always greater when the drug is administered intravenously than orally.
b. refers to the systemic availability of the major metabolite of the drug.
c. will be the same for all dosage forms if the same amounts of the drug is used.
d. can be determined by estimating the area under the concentration-effect
curve.
56. With regards to gastrointestinal absorption of drugs:
a. strongly acidic drugs are poorly absorbed from the intestines.
b. delayed gastric emptying usually reduces the amount but not the rate of
absorption.
c. tetracycline absorption increases in the presence of calcium containing
compounds.
d. a rapid transit rate may result insufficient absorption of digoxin.
57. Thiopentone is ultra-short acting because it undergoes:
a. significant first-pass effect.
b. rapid distribution into the brain.
c. rapid redistribution.
d. rapid dissociation from plasma protein binding.
58. With regards to biotransformation of drugs by the liver:
a. children usually have a much lower metabolizing capacity than adults.
b. overdosage is less likely to occur if a drug undergoes capacity-limited
metabolism.
c. maximum clearance possible is equal to the hepatic blood flow rate.
d. for drugs with a high extraction ratio, clearance is unaffected by minor
changes in enzyme activity.
59. Drugs which undergo capacity-limited metabolism:
a. have a high therapeutic index.
b. produce tolerance rapidly.
c. plasma half-life will be dependent on dosage used.
d. includes propranolol.
60. The MFO system:
a. is located on the smooth endoplasmic reticulum of the liver.
b. acts on many pharmacologically unrelated drugs.
c. can convert paracetamol to toxic metabolites.
d. can be inhibited by different classes of drugs.
61.
a.
b.
c.
d.
The following drugs are excreted mainly unchanged:
chlorpropamide.
gentamicin.
diazepam.
propranolol.
62.
a.
b.
c.
d.
Cumulative toxicity is more likely to occur if a drug
undergoes zero-order elimination.
dissociates readily into the urine.
is highly lipid soluble.
undergoes entero-hepatic cycling.
63.
a.
b.
c.
d.
The plasma elimination t1/2 of a drug:
is inversely related to its clearance.
is shorter after intravenous compared to oral administration.
is not affected by changes in its apparent volume of distribution.
largely determines its duration of action.
64.
a.
b.
c.
d.
The fraction of the total receptors to which a drug is bound is a function of:
the drug concentration.
the maximum drug effect.
the dissociation constant for the drug-receptor.
the potency of the drug.
65. A competitive antagonist:
a. acts through the same receptors as the corresponding agonist.
b.
c.
d.
shifts the dose-response curve to the right.
is reversible.
decreases the maximal response that can be obtained from a tissue.
66. Drug-receptor interaction:
a. non-competitive antagonist binds irreversibly with the receptor.
b. more potent drug is not as useful clinically as a drug that is less potent but
has higher efficacy.
c. substances that do not interact with receptors have no pharmacological
effects.
d. the magnitude of a response is directly proportional to the rate of occupation
of the receptor by the agonist.
67. The following refer to the renal clearance of drugs:
a. highly lipid-soluble drugs undergo excretion more readily.
b. an acidic drug with pKa 1.5 will be largely reabsorbed at urine pH 5.5.
c. theophylline is excreted mainly unchanged.
d. excretion can involve active as well as passive processes.
68. With regards to binding of drugs to plasma proteins:
a. binding tends to limit the the elimination of drugs which undergo renal
tubular secretion.
b. the greater the degree of binding of a drug, the longer will be its half-life.
c. hypoalbuminaemia can cause an increase in total plasma concentration of
some drugs.
d. a drug with a low binding capacity is more likely to cause adverse effects
when displaced from binding.
69. The following decrease intra-ocular pressure:
a. pilocarpine.
b. tropicamide.
c. timolol.
d. promethazine.
70. The following drugs can cause mydriasis:
a. atropine.
b. physostigmine.
c. morphine.
d. ephedrine.
71.
a.
b.
c.
d.
Noradrenaline is the neurotransmitter at:
sympathetic preganglionic fibers.
parasympathetic postganglionic fibers.
parasympathetic fibers.
sympathetic postganglionic fibers to the heart.
72. Which of the following compounds is / are related to the structure of
catecholamines?
a. dopamine.
b. tyramine.
c. ephedrine.
d. isoprenaline.
73. Which of the following statements concerning infusion of catecholamines is
/ are true?
a. noradrenaline increases pulse rate.
b. isoprenaline increases pulse rate.
c. isoprenaline increases peripheral resistance.
d. noradrenaline increases blood pressure.
74.
a.
b.
c.
d.
The following refer to sympathomimetic drugs:
all sympathomimetic drugs produce their effects by acting on an adrenoceptor.
non-catecholamines do not cross the blood-brain barrier.
ephedrine is orally active.
the effect of amphetamine is prolonged in patients with alkalinized urine.
75. Which statement(s) is / are true concerning adrenoceptor antagonists?
a. phenytoin produces a non-competitive blockade.
b. propranolol has more intrinsic activity than proctalol.
c. metoprolol is a relatively selective beta-antagonist.
d. labetalol is an antagonist of alpha and beta adrenoceptors.
76. Neuromuscular blockade is antagonized by:
a. neostigmine.
b. halothane.
c. ampicillin.
d. streptomycin.
77. In the isolated rabbit small intestine preparation,
a. phentolamine stimulates beta-adrenergic receptors to produce contraction.
b. inhibition of contraction by isoprenaline are antagonized by propranolol.
c. phentolamine increases spontaneous contraction.
d. propranolol has significant action on spontaneous contraction.
78. Plasma T1/2 of a drug:
a. is the same as biological T1/2.
b. is the time required for concentration of drug in plasma to be reduced by 1/2.
c. is usually lengthened if biologically active metabolites are formed.
d. determine steady state clearance.
79. Acetylcholine is the neurotransmitter at:
a. sympathetic preganglionic nerve fibers.
b. sympathetic postganglionic fibres to the heart.
c. parasympathetic preganglionic fibres.
d. parasympathetic postganglionic fibres.
80. D-tubocurarine:
a. is a quarternary ammonium compound.
b. causes depolarizing type of neuromuscular blockade.
c. has a shorter duration of action than succinylcholine.
d. causes hypotension by blocking autonomic ganglia and stimulating histamine
release from tissues.
81. Succinylcholine:
a. produces depolarizing neuromuscular blockade.
b. action is enhanced by parathion.
c. has long duration of action.
d. causes flaccid paralysis in chicks.
82.
a.
b.
c.
d.
The following statement(s) about sympathomimetics is / are correct:
sympathetic innervation is necessary for the action of catecholamines.
infusion of noradrenaline increases diastolic and systolic mean blood pressure.
infusion of adrenaline increases pulse rate in man.
non-catechol sympathomimetics are poor substrates of COMT and MAO.
83.
a.
b.
c.
d.
Catecholamines are used:
to prolong the action of LA.
to treat hyperthyroidism.
in the management of shock.
to treat pulmonary edema.
84. At sympathetic nerve terminals:
a. noradrenaline can activate presynaptic alpha1 receptors to inhibit further
exocytic release of noradrenaline.
b. TCAs inhibit membrane uptake mechanism for noradrenaline.
c. exocytosis of noradrenaline is stimulated by indirectly acting
sympathomimetics.
d. the hydroxylation of tyrosine is regulated by feedback inhibition by
noradrenaline.
85.
a.
b.
c.
d.
State true or false:
alpha1 adrenoceptors are more sensitive to isoprenaline than to adrenaline.
beta1 receptors are more sensitive to isoprenaline than to adrenaline.
alpha2 receptors are more sensitive to noradrenaline than to isoprenaline.
beta2 receptors are more sensitive to noradrenaline than to adrenaline.
86. State true or false:
a. amphetamines decrease both diastolic and systolic blood pressure.
b. the d-isomer of amphetamine is more potent than l-isomer.
c. the effects of amphetamine on the CNS last only a few minutes.
d. amphetamine produces reflex tachycardia.
87.
a.
b.
c.
d.
Propranolol and metoprolol have similar:
apparent volume of distribution.
bioavailability.
plasma protein binding.
half-life.
88. Histamine:
a. is formed by methylation of histidine.
b. release from mast cells is stimulated by high concentration of cAMP.
c. is metabolized mainly to N-methyl imidazole acetic acid.
d. may be released from storage sites by morphine.
89. The distribution of a drug:
a. from the circulation only involves the free unbound fraction.
b. into the brain may be more restrictive than into other tissues.
c. across the placenta only with lipid soluble drugs.
d. into the intracellular fluid is generally greater for a basic than for an acidic
compound.
90. Succinylcholine:
a. is used as a muscle relaxant.
b. is longer-acting than tubocurarine.
c. depolarizes the nicotinic receptors at the neuromuscular junction.
d. is rapidly excreted by the kidneys.
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